This invention relates to a grid for supporting tubes in steam generators, heat exchangers and the like. In conventional apparatus, as steam generators for use, for example, in a P.W.R. reactor system, conventional tube plates, welded tube grid supports and more recent tube grid supports with mechanical fitting joints (produced with grooves in the strip ends) are used to receive the tubes or pipes and to support them during the assembling of the tube bundle in said steam generator and during the operating time.
The application of such prior art tube supports has caused sometimes assembling and operating problems, such as fretting and denting between the tubes and the tube support (as in the case of tube plate in carbon steel) and fretting between the strip ends and the external frame (as in the case of grid supports), with the consequent production in that region of corrosion products, such as magnetite, that may attack the integrity of the tubes and of the support and therefore may substantially reduce the reliability and the security of the apparatus.
The present invention is directed to a solution of such problems and has as a general objective the provision of a novel tube grid support, wherein the supported tubes, the support grid and particularly the mechanical fitting joints between the strip ends and the peripheral frame structure have increased rigidity and are not subjected to chemical, mechanical and/or thermic stresses during the assembling and/or the operating time. A further object of the present invention is to provide a tube grid support, which is economical to manufacture, rigid in construction, rigid during the assembling in the apparatus, during the transportation and erection of the apparatus at the site, elastic in operation and reliable for long operating time.